Starting Heat-Lovers from Seed

By Susan Littlefield

Tomatoes, peppers, and eggplant. This trio of relatives -- all members of the Solanaceae family -- are mainstays of the summer garden. All relish warm soil and warm weather, and none will withstand frost. So gardeners must wait until the soil is toasty and they are sure that Jack Frost won't pay a final visit before putting these heat lovers in the ground. This means that, in most parts of the country, started plants must be set out in the garden in order to reap a harvest before Jack comes calling once again in the fall. Plants grown from seed sown directly in the garden just won't have enough time to ripen a crop before cold weather shuts them down.

While you can purchase seedlings of tomatoes, peppers, and eggplant at garden stores and greenhouses, the selection of varieties to choose from is often limited. Starting your own plants from seed not only lets you choose from a wider selection of varieties, it's easy and fun as well!

Getting Started

You don't need a lot of equipment or supplies to begin seed starting at home. Probably your most important investment is a fluorescent light fixture to provide young plants with plenty of light. Although you can put seedlings on a sunny windowsill, the light coming in is much lower in intensity than outdoor sunlight. Providing supplemental artificial light will give you the most successful results. A shop fixture with two cool-white bulbs is sufficient and not terribly expensive. Suspend the fixture on chains so that you can easily change its height above the plants as they grow.

Other basic supplies needed include soilless seed starting medium, cell packs and pots to plant and transplant into, liquid fertilizer, a small watering can -- and seeds, of course! In the handy, but not required, category are a heat mat to speed germination, an automatic timer to turn lights on and off, and a small fan to provide air movement around seedlings.

A Tasty Trio

Here is just a sampling of the many varieties of tomatoes, eggplants, and sweet and hot peppers we offer. Expand your garden horizons and try something new in your garden this season!

Sow seeds in individual cells of a cell pack, 2-3 seeds per cell, placing seeds 1/4 inch deep in moistened soilless potting medium. Use a heat mat to speed germination. If you don't have a heat mat, try placing containers on a warm surface such as the top of a refrigerator or hot water heater.

Once seeds sprout, put seedlings under lights hung just a couple of inches above the young plants. Keep lights on 14-16 hours a day; using an automatic timer makes this easy. As the seedlings grow, raise the light fixture so that the bulbs remain just a couple of inches above the tops of the plants.

When seedlings develop their first set of true leaves (the second pair of leaves that form), cut off the weaker seedlings at the soil line with a small pair of scissors, leaving one per cell.

When the leaves of the seedlings touch, transplant them into 4-inch pots. Fertilize growing plants weekly with a dilute solution of soluble fertilizer such as fish emulsion. Gently brush your hand over the tops of the seedlings a couple of times a day to produce sturdy stems.

Seven to ten days before outdoor planting time, begin to "harden off" seedlings to prepare them for life in the great outdoors. Start by setting them outside in a lightly shaded spot for an hour or two. Gradually increase the length of time spent outside and the amount of sun plants get so that they'll be well adapted to outdoor conditions before they go into the ground.

Tomato Tips

Start your tomato seeds 6 to 8 weeks before it's time for plants to go out in the garden, which is a week or two after the average last spring frost date. If your goal is to be the first on the block with a ripe tomato, start a few plants of an early-maturing variety a week or two before your main seed-sowing date, and set them out early with some protection into soil that has been pre-warmed by covering with black plastic. Then keep your fingers crossed!

Bottom warmth from a heat mat will speed seed germination. But once seedlings are up, give the plants cooler growing conditions. Average room temperatures (between 65-70 degrees F), with a 5 to 10 degree drop at night, are ideal.

When you set your transplants in the garden, plant them deep, up to the first set of leaves. They'll form roots along the part of the stem that is underground.

Pepper Pointers

Pepper seedlings are slower growers than tomatoes, so start them 8 to 10 weeks before their planting-out date, which is two weeks after the last frost date. Don't put peppers out too early; young plants exposed to too cold conditions may survive, but they won't bear well. As with tomatoes, bottom heat will speed seed germination, and peppers will appreciate warmer temperatures for growing on. If you can, give young seedling daytime temperatures of 70-75 degrees F, with a drop to 65 degrees F at night. Use lukewarm water when you water your pepper seedlings.

Set pepper transplants at the same depth as they were growing in the pot when you transplant them to the garden.

Eggplant Advice

Start seeds 10 weeks before their setting-out date, which is at least two weeks after the last expected frost. Eggplants are warmth lovers like peppers, so use a heat mat for germination and give seedlings 70 to 80 degree F daytime growing temperatures, with nighttime temperatures no lower than 65 degrees F. Eggplant doesn't bounce back well from stress, so make sure that seedlings get plenty of light, consistent moisture, and regular fertilization as they grow.

Question of the Month: Hot Weather and Tomatoes

Q: I live in Texas where it can get really hot in the summer. I know tomatoes like heat, but can it get too hot for them?

A: It can indeed get too hot for tomatoes to fruit. When daytime temperatures climb above 90 degrees F or remain above 70 degrees F at night for several days, tomatoes may fail to set fruit. Once the weather cools off, plants will begin bearing again. One strategy gardeners in long-season, hot summer areas can use to avoid this problem is to cultivate two crops of tomatoes. Grow a spring-planted crop for harvest before the scorching heat of midsummer arrives, then set out a second set of transplants in July for an additional harvest in the more moderate weather of early fall up until frost.